“People working at places that use thermal paper can have continual contact with bisphenol A. And if they knew, I think they would be horrified,” notes Koni Grob, an analytical chemist with an official government food laboratory in Zurich, Switzerland. He’s describing the thermal paper commonly used throughout Europe and North America to print store receipts.

Grob’s team was the first of three to publish data in July on the presence of bisphenol A, a thermal-printing aid — and hormone mimic...